Electronic device

ABSTRACT

An electronic device is provided. The electronic device includes a substrate, a driving circuit, a diode and a light shielding element. The driving circuit is disposed on the substrate. The diode is electrically connected to the driving circuit. The light shielding element overlaps the substrate. A surface of the light shielding element has a first width. A cross-sectional-surface of a portion of the light shielding element has a second width. In addition, the second width is greater than the first width in a cross-sectional view, and the surface is closer to the substrate than the cross-sectional surface of the portion.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of pending U.S. Ser. No. 16/924,447,filed on Jul. 9, 2020, which is a Continuation of application Ser. No.16/222,136, filed on Dec. 17, 2018 (now U.S. Pat. No. 10,749,090, issuedAug. 18, 2020), which is a Continuation of application Ser. No.15/855,062, filed on Dec. 27, 2017 (now U.S. Pat. No. 10,193,042, issuedJan. 29, 2019), the entirety of which are incorporated by referenceherein.

BACKGROUND Technical Field

The present disclosure relates to a display device. The disclosure inparticular relates to a protective layer of the display device.

Description of the Related Art

Electronic products that come with a display panel, such as smartphones,tablets, notebooks, monitors, and TVs, have become indispensablenecessities in modern society. With the flourishing development of suchportable electronic products, consumers have higher expectationsregarding the quality, the functionality, and the price of suchproducts. The development of next-generation display devices has beenfocused on techniques that are energy saving and environmentallyfriendly.

Light-emitting diodes (LEDs) based upon gallium nitride (GaN) areexpected to be used in future high-efficiency lighting applications,replacing incandescent and fluorescent lighting lamps. Current GaN-basedLED devices are prepared by heteroepitaxial growth techniques onsubstrate materials. A typical wafer level LED device structure mayinclude a lower n-doped GaN layer formed over a sapphire substrate, asingle quantum well (SQW) or multiple quantum well (MWQ), and an upperp-doped GaN layer.

Micro-LED technology is an emerging flat panel display technology. MicroLED displays drives an array of addressed micro LEDs. In the currentmanufacturing method, micro LEDs are formed and diced into several microLED dies (e.g., micro-lighting dies). The driving circuits and relatedcircuits are formed on the glass substrate to provide an array substrate(e.g., TFT array substrate), and the micro LED dies are then mounted onthe array substrate. Bare dies are commonly used in micro LEDs, whereinthe bare dies are surrounded by a protective layer such as ananisotropic conductive film (ACF) layer. An ACF layer may serve as aconductive route between the electrode of micro LED and the TFT arraysubstrate. Typically, the top surface of an ACF layer is level with thatof a micro LED so as to provide protection. However, this results in awaste of ACF material and it limits the space for filling the lightconversion layer. In addition, conductive particles having varying sizesin the ACF layer may also lead to poor conductivity or poorreflectivity.

Accordingly, it is desirable to develop a design that employs protectivelayers, which can effectively maintain or improve the performance of LEDstructures.

SUMMARY

In accordance with some embodiments of the present disclosure, anelectronic device is provided. The electronic device includes asubstrate, a driving circuit, a diode and a light shielding element. Thedriving circuit is disposed on the substrate. The diode is electricallyconnected to the driving circuit. The light shielding element overlapsthe substrate. A surface of the light shielding element has a firstwidth. A cross-sectional-surface of a portion of the light shieldingelement has a second width. In addition, the second width is greaterthan the first width in a cross-sectional view, and the surface iscloser to the substrate than the cross-sectional surface of the portion.

A detailed description is given in the following embodiments withreference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure may be more fully understood by reading the subsequentdetailed description and examples with references made to theaccompanying drawings, wherein:

FIGS. 1A-1C illustrate the cross-sectional views of the display devicein accordance with some embodiments of the present disclosure.

FIGS. 2A-2C illustrate the cross-sectional views of the display devicein accordance with some embodiments of the present disclosure.

FIGS. 3A-3B illustrate the cross-sectional views of the display devicein accordance with some embodiments of the present disclosure.

FIG. 4 illustrates the cross-sectional view of the display device inaccordance with some embodiments of the present disclosure.

FIGS. 5A-5C illustrate the cross-sectional views of the display devicein accordance with some embodiments of the present disclosure.

FIGS. 6A-6B illustrate the cross-sectional views of the display devicein accordance with some embodiments of the present disclosure.

FIG. 7 illustrates the cross-sectional view of the display device inaccordance with some embodiments of the present disclosure.

FIG. 8 illustrates the cross-sectional view of the display device inaccordance with some embodiments of the present disclosure.

FIG. 9A illustrates a partially enlarged portion of the display deviceas shown in FIG. 5A.

FIGS. 9B-9E illustrate the cross-sectional views of the first conductiveelement in accordance with some embodiments of the present disclosure.

DETAILED DESCRIPTION

The display device of the present disclosure and the manufacturingmethod thereof are described in detail in the following description. Inthe following detailed description, for purposes of explanation,numerous specific details and embodiments are set forth in order toprovide a thorough understanding of the present disclosure. The specificelements and configurations described in the following detaileddescription are set forth in order to clearly describe the presentdisclosure. It will be apparent, however, that the exemplary embodimentsset forth herein are used merely for the purpose of illustration, andthe inventive concept may be embodied in various forms without beinglimited to those exemplary embodiments. In addition, the drawings ofdifferent embodiments may use like and/or corresponding numerals todenote like and/or corresponding elements in order to clearly describethe present disclosure. However, the use of like and/or correspondingnumerals in the drawings of different embodiments does not suggest anycorrelation between different embodiments. In addition, in thisspecification, expressions such as “first material layer disposedon/over a second material layer”, may indicate the direct contact of thefirst material layer and the second material layer, or it may indicate anon-contact state with one or more intermediate layers between the firstmaterial layer and the second material layer. In the above situation,the first material layer may not be in direct contact with the secondmaterial layer.

It should be noted that the elements or devices in the drawings of thepresent disclosure may be present in any form or configuration known tothose with ordinary skill in the art. In addition, the expressions “alayer overlying another layer”, “a layer is disposed above anotherlayer”, “a layer is disposed on another layer” and “a layer is disposedover another layer” may indicate that the layer is in direct contactwith the other layer, or that the layer is not in direct contact withthe other layer, there being one or more intermediate layers disposedbetween the layer and the other layer.

In addition, in this specification, relative expressions are used. Forexample, “lower”, “bottom”, “higher” or “top” are used to describe theposition of one element relative to another. It should be appreciatedthat if a device is flipped upside down, an element that is “lower” willbecome an element that is “higher”.

It should be understood that, although the terms first, second, thirdetc. may be used herein to describe various elements, components,regions, layers, portions and/or sections, these elements, components,regions, layers, portions and/or sections should not be limited by theseterms. These terms are only used to distinguish one element, component,region, layer, portion or section from another region, layer or section.Thus, a first element, component, region, layer, portion or sectiondiscussed below could be termed a second element, component, region,layer, portion or section without departing from the teachings of thepresent disclosure.

It should be understood that this description of the exemplaryembodiments is intended to be read in connection with the accompanyingdrawings, which are to be considered part of the entire writtendescription. The drawings are not drawn to scale. In addition,structures and devices are shown schematically in order to simplify thedrawing.

The terms “about” and “substantially” typically mean +/−20% of thestated value, more typically +/−10% of the stated value, more typically+/−5% of the stated value, more typically +/−3% of the stated value,more typically +/−2% of the stated value, more typically +/−1% of thestated value and even more typically +/−0.5% of the stated value. Thestated value of the present disclosure is an approximate value. Whenthere is no specific description, the stated value includes the meaningof “about” or “substantially”.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this disclosure belongs. It should be appreciated that,in each case, the term, which is defined in a commonly used dictionary,should be interpreted as having a meaning that conforms to the relativeskills of the present disclosure and the background or the context ofthe present disclosure, and should not be interpreted in an idealized oroverly formal manner unless so defined.

In addition, in some embodiments of the present disclosure, termsconcerning attachments, coupling and the like, such as “connected” and“interconnected,” refer to a relationship wherein structures are securedor attached to one another either directly or indirectly throughintervening structures, as well as both movable or rigid attachments orrelationships, unless expressly described otherwise.

The term “elevation” used herein means the distance from a substrate toa target surface. In particular, the term “elevation” may refer to thedistance from a substantially planar region of a substrate to a targetsurface. For example, in accordance with some embodiments illustratedherein, an evaluation may refer to the distance from the bottom surfaceof a substrate to a target surface.

The display device provided in the present disclosure includes aprotective layer having the elevation that is lower than the elevationof the upper semiconductor layer of the light-emitting unit (e.g., LED,micro LED and so on). In this case, less material is required for theprotective layer compared to general display devices where the elevationof the protective layer is level with that of the upper semiconductorlayer. In addition, there will be more space for the wavelengthconversion layer, which is disposed over the protective layer, to fillin. In accordance with some embodiments of the present disclosure, thedisplay device includes the protective layer having the elevation thatis higher than the elevation of the quantum well of the light-emittingunit so as to prevent moisture and oxygen from damaging the quantumwell. Furthermore, the protective layer of such a design may alsoprevent shorts or increase the reflectivity. Moreover, in accordancewith some embodiments of the present disclosure, the display deviceincludes a buffer layer disposed between the light emitting unit and thewavelength conversion layer so that the wavelength conversion layer maybe unaffected by the current or heat produced by the lightemitting-unit.

FIG. 1A illustrates a cross-sectional view of the display device 10 inaccordance with some embodiments of the present disclosure. It should beunderstood that additional features may be added to the display devicein some embodiments of the present disclosure. In another embodiment ofthe present disclosure, some of the features described below may bereplaced or eliminated.

Referring to FIG. 1A, the display device 10 may include a drivingsubstrate 100, a light-emitting unit 200 and a first protective layer300. The driving substrate 100 may include a substrate 102, a drivingcircuit 104, a gate dielectric layer 106, a first insulating layer 108and a second insulating layer 110. The driving substrate 100 may serveas a switch of the light-emitting unit 200. As shown in FIG. 1A, thedriving circuit 104 is disposed on the substrate 102. In someembodiments of the present disclosure, the substrate 102 may include,but is not limited to, glass, quartz, sapphire, polycarbonate (PC),polyimide (PI), polyethylene terephthalate (PET), rubbers, glass fibers,other polymer materials, any other suitable substrate material, or acombination thereof. In some other embodiments of the presentdisclosure, the substrate 102 may be made of a metal-glass fibercomposite plate, a metal-ceramic composite plate, a printed circuitboard, or any other suitable material, but it is not limited thereto. Itshould be understood that although the driving circuit 104 in someembodiments as illustrated in figures is an active driving circuitincluding thin-film transistors (TFT), the driving circuit 104 may be apassive driving circuit in accordance with another embodiment. In someembodiments, the driving circuit 104 may be controlled by an IC or amicrochip. For example, in this embodiment, the driving circuit 104 mayinclude the conductive layer, the insulating layer and the active layer,which serve as a TFT. The active layer may include semiconductormaterials such as amorphous silicon, polysilicon or metal oxide. Theactive layer may include a pair of source/drain regions doped withsuitable dopants and an undoped channel region formed between thesource/drain regions.

The gate dielectric layer 106, the first insulating layer 108 and thesecond insulating layer 110 are sequentially disposed on the substrate102. The driving circuit 104 may be surrounded by the gate dielectriclayer 106, the first insulating layer 108 and the second insulatinglayer 110. In some embodiments of the present disclosure, the materialof the gate dielectric layer 106 may include silicon oxide, siliconnitride, silicon oxynitride, high-k dielectric material, any othersuitable dielectric material, or a combination thereof. The high-kdielectric material may include, but is not limited to, metal oxide,metal nitride, metal silicide, transition metal oxide, transition metalnitride, transition metal silicide, metal oxynitride, metal aluminate,zirconium silicate, zirconium aluminate. In some embodiments of thepresent disclosure, the materials of the first insulating layer 108 orthe second insulating layer 110 may be formed of an organic material, aninorganic material or a combination thereof. The organic material mayinclude, but is not limited to, an acrylic or methacrylic organiccompound, isoprene compound, phenol-formaldehyde resin, benzocyclobutene(BCB), PECB (perfluorocyclobutane) or a combination thereof. Theinorganic material may include, but is not limited to, silicon nitride,silicon oxide, or silicon oxynitride or a combination thereof.

In some embodiments of the present disclosure, the gate dielectric layer106, the first insulating layer 108 or the second insulating layer 110may be formed by using chemical vapor deposition or spin-on coating. Thechemical vapor deposition may include, but is not limited to,low-pressure chemical vapor deposition (LPCVD), low-temperature chemicalvapor deposition (LTCVD), rapid thermal chemical vapor deposition(RTCVD), plasma enhanced chemical vapor deposition (PECVD), atomic layerdeposition (ALD), or any other suitable method.

Still referring to FIG. 1A, the light-emitting unit 200 may be disposedon the driving substrate 100. The light-emitting unit 200 may bedisposed on the driving circuit 104 and electrically connected to thedriving circuit 104. Specifically, the light-emitting unit 200 may becoupled to the driving circuit 104 through the vias and the pads. Thelight-emitting unit 200 may include a first semiconductor layer 202, aquantum well layer 204 disposed on the first semiconductor layer 202 anda second semiconductor layer 206 disposed on the quantum well layer 204.The light-emitting unit 202 may include LED or micro LED. In accordancewith some embodiments of the present disclosure, the cross-sectionalarea of the light emitting unit 200 may have a length of about 1 μm toabout 150 μm and may have a width ranging from about 1 μm to about 150μm. In some embodiments, the light emitting unit 200 may have a sizeranging from about 1 μm × 1 μm × 1 μm to about 150 μm × 150 μm × 150 μm.

In some embodiments of the present disclosure, the first semiconductorlayer 202 may be formed of the III-V compounds having dopants of thefirst conductivity type, e.g. gallium nitride having p-type conductivity(p-GaN). In some embodiments of the present disclosure, the quantum welllayer 204 may include a homogeneous interface, a heterogeneousinterface, a single quantum well (SQW) or a multiple quantum well (MQW).The material of the quantum well layer 204 may include, but is notlimited to, indium gallium nitride, a gallium nitride or a combinationthereof. In some embodiments of the present disclosure, the secondsemiconductor layer 206 may be formed of the III-V compounds havingdopants of the second conductivity type, e.g. gallium nitride havingn-type conductivity (n-GaN). In addition, the above III-V compounds mayinclude, but is not limited to, indium nitride (InN), aluminum nitride(AlN), indium gallium nitride (InGaN), aluminum gallium nitride (AlGaN),aluminum indium gallium nitride (AlGaInN) or a combination thereof.

In some embodiments of the present disclosure, the first semiconductorlayer 202, the quantum well layer 204 or the second semiconductor layer206 may be formed by using an epitaxial growth process. For example,metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy(MBE), hydride vapor phase epitaxy (HYPE), liquid phase epitaxy (LPE),or another suitable process may be used to form the first semiconductorlayer 202, the quantum well layer 204 or the second semiconductor layer206.

The light-emitting unit 200 may further include a first electrode 208and a second electrode 210. In accordance with some embodiments of thepresent disclosure, the first electrode 208 and the second electrode 210may serve as the n-electrode and p-electrode of the light-emitting unit200. In some embodiments, the first electrode 208 and/or the secondelectrode 210 may be formed of metallic conductive materials,transparent conductive materials or a combination thereof. The metallicconductive material may include, but is not limited to, copper,aluminum, tungsten, titanium, gold, platinum, nickel, copper alloys,aluminum alloys, tungsten alloys, titanium alloys, gold alloys, platinumalloys, nickel alloys, any other suitable metallic conductive materials,or a combination thereof. The transparent conductive material mayinclude transparent conductive oxides (TCO). For example, thetransparent conductive material may include, but is not limited to,indium tin oxide (ITO), tin oxide (SnO), zinc oxide (ZnO), indium zincoxide (IZO), indium gallium zinc oxide (IGZO), indium tin oxide (ITZO),antimony tin oxide (ATO), antimony zinc oxide (AZO), any other suitabletransparent conductive materials, or a combination thereof. In someembodiments of the present disclosure, the first electrode 208 and thesecond electrode 210 may be formed by, but is not limited to, chemicalvapor deposition, physical vapor deposition, electroplating process,electroless plating process, any other suitable processes, or acombination thereof. The chemical vapor deposition may include, but isnot limited to, low-pressure chemical vapor deposition (LPCVD),low-temperature chemical vapor deposition (LTCVD), rapid thermalchemical vapor deposition (RTCVD), plasma enhanced chemical vapordeposition (PECVD), atomic layer deposition (ALD), or any other suitablemethod. The physical vapor deposition may include, but is not limitedto, sputtering, evaporation, pulsed laser deposition (PLD), or any othersuitable method.

Still referring to FIG. 1A, the first protective layer 300 is disposedon the driving substrate 100 and adjacent to light-emitting unit 200. Inother words, the light-emitting unit 200 is surrounded by the firstprotective layer 300. The first protective layer 300 may preventmoisture or oxygen from damaging the quantum well layer 204 of thelight-emitting unit 200. In some embodiments of the present disclosure,the first protective layer 300 may be transparent or semi-transparent tothe visible wavelength so as to not significantly degrade the lightextraction efficiency of the display device. The first protective layer300 may be formed of organic materials or inorganic materials. In someembodiments, the inorganic material may include, but is not limited to,silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, anyother suitable protective materials, or a combination thereof. In someembodiments, the organic material may include, but is not limited to,epoxy resins, acrylic resins such as polymethylmetacrylate (PMMA),benzocyclobutene (BCB), polyimide, and polyester, polydimethylsiloxane(PDMS), any other suitable protective materials, or a combinationthereof.

In some embodiments of the present disclosure, the first protectivelayer 300 may be formed by using chemical vapor deposition (CVD),spin-on coating or printing. The chemical vapor deposition may include,but is not limited to, low-pressure chemical vapor deposition (LPCVD),low-temperature chemical vapor deposition (LTCVD), rapid thermalchemical vapor deposition (RTCVD), plasma enhanced chemical vapordeposition (PECVD), atomic layer deposition (ALD), or any other suitablemethod.

In addition, the first protective layer 300 may further include aplurality of conductive elements 302 formed therein. As shown in FIG.1A, some of the conductive elements 302 may be dispersed in the firstprotective layer 300, and some of the conductive elements 302 may beformed on the second insulating layer 110 in accordance with someembodiments of the present disclosure. In particular, the conductiveelements 302 may further include the first conductive elements 302 a andthe second conductive elements 302 b. The first conductive elements 302a are disposed underneath a first terminal S1 of the light-emitting unit200. The first terminal S1 is opposed to a second terminal S2. In someembodiments, the first terminal S1 and the second terminal S2 may referto the bottom and the top of the light-emitting unit 200 respectively.

The first conductive elements 302 a may be disposed between thelight-emitting unit 200 and the driving substrate 100. Specifically, thefirst conductive elements 302 a may be disposed between the firstelectrode 208 and the second insulating layer 110 or the secondelectrode 210 and the second insulating layer 110. The first conductiveelements 302 a may be disposed between the first electrode 208 and thecontact pads on the second insulating layer 110 or the second electrode210 and the contact pads on the second insulating layer 110. Inaddition, the first conductive elements 302 a may electrically connectthe first electrode 208 or the second electrode 210 with the drivingcircuit 104. On the other hand, the second conductive elements 302 b maybe disposed in the region out of the light-emitting unit 200. The secondconductive elements 302 b may be dispersed in the first protective layer300. The second conductive elements 302 b also may be disposed at thebottom of the first protective layer 300.

The conductive elements 302 may be formed of conductive materials toserve as an electrical contact of the light-emitting unit 200. Theconductive elements 302 may also serve as reflective particles toreflect the light emitted by light-emitting unit 200. In someembodiments of the present disclosure, the conductive elements 302 maybe formed of high reflective conductive materials. In some embodiments,the material of the conductive element 302 may include, but is notlimited to, gold, platinum, silver, copper, iron, nickel, tin, aluminum,magnesium, palladium, iridium, rhodium, ruthenium, zinc, gold alloys,platinum alloys, silver alloys, copper alloys, iron alloys, nickelalloys, tin alloys, aluminum alloys, magnesium alloys, palladium alloys,iridium alloys, rhodium alloys, ruthenium alloys, zinc alloys, any othersuitable conductive materials, or a combination thereof. In addition,further details regarding the conductive elements 302 will be discussedlater.

As shown in FIG. 1A, the second semiconductor layer 206 of thelight-emitting unit 200 includes a top surface 206 a. The firstprotective layer 300 includes a top surface 300 a. In some embodimentsof the present disclosure, the elevation E1 of the top surface 206 a ofthe second semiconductor layer 206 is higher than the elevation E2 ofthe top surface 300 a of the first protective layer 300. It should benoted that the term “elevation” used herein refers to the distance fromthe substrate 102 to a target surface. Specifically, the term“elevation” may refer to the distance from the bottom surface thesubstrate 102 to a target surface. For example, the elevation E1 of thetop surface 206 a is defined as the distance from the substrate 102 tothe top surface 206 a.

As described above, the elevation E1 of the top surface 206 a of thesecond semiconductor layer 206 is higher than the elevation E2 of thetop surface 300 a of the first protective layer 300. In this way, lessmaterial is required to form the protective layer 300 so that thematerial may be saved, compared with conventional display devices wherethe elevation of the protective layer is substantially level with thatof the upper semiconductor layer (e.g., the second semiconductor layer206). In addition, there will be more space for the wavelengthconversion layer 304 to fill in so that the optical performance of thedisplay device may be improved. In some embodiments of the presentdisclosure, the difference between the elevation E1 of the secondsemiconductor layer 206 and the elevation E2 of the first protectivelayer 300 ranges from about 0.02 μm to about 5 μm, or from about 0.2 μmto about 2 It should be noted that the difference between the elevationE1 and the elevation E2 should not be too small, or the space where theadditional portions 304′ may be filled will be reduced and thus theillumination efficiency will be decreased and the benefit of materialsaving may not be achieved; and the difference between the elevation E1and the elevation E2 should not be too great, or the protectingefficiency of the first protective layer 300 will be reduced and thelight-emitting unit 200 may become easily affected by the environment.

Moreover, as shown in FIG. 1A, the quantum well layer 204 of thelight-emitting unit 200 includes a top surface 204 a. In someembodiments of the present disclosure, the elevation E2 of the topsurface 300 a of the first protective layer 300 is higher than theelevation E3 of the top surface 204 a of the quantum well layer 204. Inother words, the quantum well layer 204 is embedded in the firstprotective layer 300. In this way, quantum well layer 204 of thelight-emitting unit 200 may be fully protected by the first protectivelayer 300 so as to prevent moisture and oxygen from affecting ordamaging the quantum well layer 204. In some embodiments of the presentdisclosure, the difference between the elevation E2 of the firstprotective layer 300 and the elevation E3 of the quantum well layer 204ranges from about 0.1 μm to about 10 or from about 1 μm to about 5 Itshould be noted that the difference between the elevation E2 and theelevation E3 should not be too small, or the protecting efficiency ofthe first protective layer 300 will be reduced and the light-emittingunit 200 may become easily affected by the environment; and thedifference between the elevation E2 and the elevation E3 should not betoo great, or the heat capacity of the light-emitting unit 200 will betoo great so that heat may be trapped in the first protective layer 300and may result in damages to the light-emitting unit 200 or thewavelength conversion layer 304 formed thereon. In addition, if thedifference between the elevation E2 and the elevation E3 is too great,the benefit of material saving also may not be achieved.

In addition, it should be understood that, although the display device10 include the wavelength conversion layer 304 disposed on thelight-emitting unit 200 in the embodiments illustrated in FIG. 1A, thewavelength conversion layer 304 may be simply replaced with atransparent material without the function of wavelength conversion(e.g., without phosphor particles or quantum dot materials). Forexample, the transparent material may include, but is not limited to, apolymer or glass matrix.

In some embodiments of the present disclosure, the top surface 300 a ofthe first protective layer 300 may be disposed at any suitable positionbetween the top surface 204 a of the quantum well layer 204 and the topsurface 206 a of the second semiconductor layer 206 as long as thequantum well layer 204 is covered by the first protective layer 300.

Next, still referring to FIG. 1A, the display device 10 may furtherinclude the wavelength conversion layer 304 disposed on thelight-emitting unit 200 and the first protective layer 300, and a lightshielding layer 306 disposed on the first protective layer 300. Thewavelength conversion layer 304 may be disposed between the lightshielding layers 306 and cover the light-emitting unit 200. The lightshielding layer 306 may define a subpixel region in the display device10. Each subpixel may correspond to a light emitting unit 200. In someembodiments, each subpixel may correspond to more than one lightemitting units 200.

In some embodiments of the present disclosure, the wavelength conversionlayer 304 includes a portion 304′ that covers a portion of the sidewall206 s of the second semiconductor layer 206. As described above, theadditional portions 304′ of the wavelength conversion layer 304 mayfurther improve the optical performance of the display device, ascompared with the conventional display devices where the top surface ofthe protective layer is substantially level with that of the uppersemiconductor layer (i.e., without the additional wavelength conversionportions).

The wavelength conversion layer 304 may include phosphors for convertingthe wavelength of light generated from the light emitting unit 200. Insome embodiments of the present disclosure, the wavelength conversionlayer 304 may include a polymer or glass matrix and a dispersion ofphosphor particles within the matrix. The light emission from the lightemitting unit 200 may be tuned to specific colors in the color spectrum.For example, the wavelength conversion layer 304 includes the phosphorsfor converting the light emitted from the light emitting unit 200 intored light, green light, blue light or the light of any other suitablecolor. In some other embodiments, the wavelength conversion layer 304includes quantum dot materials. The quantum dot material may have acore-shell structure. The core may include, but is not limited to, CdSe,CdTe, CdS, ZnS, ZnSe, ZnO, ZnTe, InAs, InP, GaP, or any other suitablematerials, or a combination thereof. The shell may include, but is notlimited to, ZnS, ZnSe, GaN, GaP, or any other suitable materials, or acombination thereof. In addition, it should be understood that althoughthe wavelength conversion layer 304 as illustrated in FIG. 1A appears tohave a convex top surface, the wavelength conversion layer 304 may haveany other suitable shapes according to needs. Similarly, theconfiguration of the light-shielding layer 306 is not limited to that asillustrated in FIG. 1A. The light-shielding layer 306 may also have anyother suitable configurations according to needs.

The light-shielding layer 306 disposed adjacent to the wavelengthconversion layer 304 may enhance the contrast of luminance. In someembodiments of the present disclosure, the light shielding layer 306 isformed of an opaque material such as a black matrix material. The blackmatrix material may include, but is not limited to, organic resins,glass pastes, and resins or pastes including black pigments, metallicparticles such as nickel, aluminum, molybdenum, and alloys thereof,metal oxide particles (e.g. chromium oxide), or metal nitride particles(e.g. chromium nitride), or any other suitable materials.

In some embodiments of the present disclosure, the wavelength conversionlayer 304 and the light shielding layer 306 may be formed by usingchemical vapor deposition (CVD), spin-on coating or printing. Thechemical vapor deposition may include, but is not limited to,low-pressure chemical vapor deposition (LPCVD), low-temperature chemicalvapor deposition (LTCVD), rapid thermal chemical vapor deposition(RTCVD), plasma enhanced chemical vapor deposition (PECVD), atomic layerdeposition (ALD), or any other suitable method.

As shown in FIG. 1A, the display device 10 may further include a secondprotective layer 308 covering the wavelength conversion layer 304 andthe light shielding layer 306. The second protective layer 308 mayprevent the wavelength conversion layer 304 and the light shieldinglayer 306 from being affected by the outer environment. The secondprotective layer 308 may be formed of organic materials or inorganicmaterials. In some embodiments, the inorganic material may include, butis not limited to, silicon nitride, silicon oxide, silicon oxynitride,aluminum oxide, any other suitable protective materials, or acombination thereof. In some embodiments, the organic material mayinclude, but is not limited to, epoxy resins, acrylic resins such aspolymethylmetacrylate (PMMA), benzocyclobutene (BCB), polyimide, andpolyester, polydimethylsiloxane (PDMS), any other suitable protectivematerials, or a combination thereof.

In some embodiments of the present disclosure, the second protectivelayer 308 may be formed by using chemical vapor deposition (CVD),spin-on coating or printing. The chemical vapor deposition may include,but is not limited to, low-pressure chemical vapor deposition (LPCVD),low-temperature chemical vapor deposition (LTCVD), rapid thermalchemical vapor deposition (RTCVD), plasma enhanced chemical vapordeposition (PECVD), atomic layer deposition (ALD), or any other suitablemethod.

In addition, the display device 10 may further include an adhesive layer310 and a cover substrate 312. The adhesive layer 310 may be disposedbetween the second protective layer 308 and the cover substrate 312 toaffix the cover substrate 312 to the second protective layer 308. Theadhesive layer 310 may be formed of any suitable adhesive material. Onthe other hand, the material of the cover substrate 312 may include, butis not limited to, glass, quartz, sapphire, polycarbonate (PC),polyimide (PI), polyethylene terephthalate (PET), any other suitablesubstrate material, or a combination thereof.

Next, FIG. 1B illustrates a cross-sectional view of the display device10 in accordance with other embodiments of the present disclosure. Itshould be noted that the same or similar elements or layers in above andbelow contexts are represented by the same or similar referencenumerals. The materials, manufacturing methods and functions of theseelements or layers are the same or similar to those described above, andthus will not be repeated herein. The difference between the embodimentsshown in FIG. 1B and FIG. 1A is that the top surface 300 a of the firstprotective layer 300 in the embodiment shown in FIG. 1B has a concaveshape while the top surface 300 a of the first protective layer 300 inthe embodiment shown in FIG. 1A is substantially planar.

As shown in FIG. 1B, the wavelength conversion layer 304 located abovethe light-emitting unit 200 has a first thickness T1, and the wavelengthconversion layer 304 including the additional portions 304′ locatedabove the protective layer 300 has a second thickness T2. In someembodiments of the present disclosure, the first thickness T1 may bedefined as the maximum thickness of the wavelength conversion layer 304that is located above the light-emitting unit 200. In some embodimentsof the present disclosure, the second thickness T2 may be defined as themaximum thickness of the wavelength conversion layer 304 that is locatedabove the protective layer 300. In this embodiment, the differencebetween the first thickness T1 and the second thickness T2 in onesubpixel may be smaller due to the concave shape of the top surface 300a, as compared with that of the substantially planar top surface 300 a(as shown in FIG. 1A). In addition, in some embodiments of the presentdisclosure, the third thickness T3 of the additional portions 304′ thatis closer to the light-emitting unit 200 may be smaller than the fourththickness T4 of the additional portions 304′ that is farther from thelight-emitting unit 200 due to the concave shape of the top surface 300a.

In some embodiments of the present disclosure, the concave shape of thetop surface 300 a may be formed due to the hydrophobic properties of thechosen materials of the first protective layer 300. In some embodimentsof the present disclosure, the concave shape of the top surface 300 amay be formed by a patterning process. The patterning process mayinclude a photolithography process and an etching process such as aselective etching process. The photolithography process may include, butis not limited to, photoresist coating (e.g., spin-on coating), softbaking, hard baking, mask aligning, exposure, post-exposure baking,developing the photoresist, rinsing, drying, and other suitableprocesses. The etching process may include dry etching process or wetetching process.

Next, FIG. 1C illustrates a cross-sectional view of the display device10 in accordance with other embodiments of the present disclosure. Thedifference between the embodiments shown in FIG. 1C and FIG. 1A is thatthe top surface 300 a of the first protective layer 300 in theembodiment shown in FIG. 1C has a convex shape while the top surface 300a of the first protective layer 300 in the embodiment shown in FIG. 1Ais substantially planar.

As shown in FIG. 1C, in this embodiment, the fifth thickness T5 of theadditional portions 304′ that is closer to the light-emitting unit 200may be greater than the sixth thickness T6 of the additional portions304′ that is farther from the light-emitting unit 200 due to the convexshape of the top surface 300 a. In addition, the reflected light L maybe concentrated to increase the illumination efficiency due to theconvex surface of the top surface 300 a.

In some embodiments of the present disclosure, the convex shape of thetop surface 300 a may be formed due to the hydrophilic properties of thechosen materials of the first protective layer 300. In some embodimentsof the present disclosure, the convex shape of the top surface 300 a maybe formed by a patterning process. The patterning process may include aphotolithography process and an etching process such as a selectiveetching process. The photolithography process may include, but is notlimited to, photoresist coating (e.g., spin-on coating), soft baking,hard baking, mask aligning, exposure, post-exposure baking, developingthe photoresist, rinsing, drying, and other suitable processes. Theetching process may include dry etching process or wet etching process.

Next, FIG. 2A illustrates a cross-sectional view of the display device20 in accordance with some embodiments of the present disclosure. Thedifference between the embodiments shown in FIG. 2A and FIG. 1A is thatthe light-emitting unit 200′ in the embodiment shown in FIG. 2A is avertical chip type light-emitting diode while the light-emitting unit200 in the embodiment shown in FIG. 1A is a flip chip typelight-emitting diode.

As shown in FIG. 2A, the light-emitting unit 200′ may be disposed on thedriving circuit 104 and electrically connected to the driving circuit104. The first electrode 208 of the light-emitting unit 200′ is disposedon the conductive elements 302 and may serve as a bottom electrode ofthe light-emitting unit 200′. The first semiconductor layer 202, thequantum well layer 204 and the second semiconductor layer 206 aresequentially stacked on the first electrode 208. The second electrode210 is disposed on the second semiconductor layer 206 and may serve as atop electrode of the light-emitting unit 200. In addition, in thisembodiment, the light-emitting unit 200′ may further include a contactlayer 212 disposed on the second electrode 210 and the first protectivelayer 300. The contact layer 212 may serve as an electrical contact ofthe light-emitting unit 200′. In some embodiments of the presentdisclosure, the contact layer 212 may be conformally formed over thesecond electrode 210 and the first protective layer 300. The contactlayer 212 may couple to the circuit from different array or to thecircuit outside the panel.

In some embodiments of the present disclosure, the material of thecontact layer 212 may include transparent conductive oxides (TCO). Forexample, the transparent conductive material may include, but is notlimited to, indium tin oxide (ITO), tin oxide (SnO), zinc oxide (ZnO),indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), indium tinoxide (ITZO), antimony tin oxide (ATO), antimony zinc oxide (AZO), anyother suitable transparent conductive materials, or a combinationthereof.

In addition, the contact layer 212 may be formed by using chemical vapordeposition (CVD) or spin-on coating. The chemical vapor deposition mayinclude, but is not limited to, low-pressure chemical vapor deposition(LPCVD), low-temperature chemical vapor deposition (LTCVD), rapidthermal chemical vapor deposition (RTCVD), plasma enhanced chemicalvapor deposition (PECVD), atomic layer deposition (ALD), or any othersuitable method.

Similar to the display device 10 in FIG. 1A, the display device 20 ofthe embodiment as shown in FIG. 2A, the elevation E1 of the top surface206 a of the second semiconductor layer 206 is higher than the elevationE2 of the top surface 300 a of the first protective layer 300. In someembodiments of the present disclosure, the difference between theelevation E1 of the second semiconductor layer 206 and the elevation E2of the first protective layer 300 ranges from about 0.02 μm to about 5μm, or from about 0.2 μm to about 2 In addition, the elevation E2 of thetop surface 300 a of the first protective layer 300 is higher than theelevation E3 of the top surface 204 a of the quantum well layer 204. Insome embodiments of the present disclosure, the difference between theelevation E2 of the first protective layer 300 and the elevation E3 ofthe quantum well layer 204 ranges from about 0.1 μm to about 10 μm, orfrom about 1 μm to about 5 μm.

Furthermore, in the display device 20 of the embodiment as shown in FIG.2A, the second electrode 210 of the light-emitting unit 200′ includes atop surface 210 a. The elevation E4 of the top surface 210 a of thesecond electrode 210 is also higher than the elevation E2 of the topsurface 300 a of the first protective layer 300. In some embodiments ofthe present disclosure, the difference between the elevation E4 of thesecond electrode 210 and the elevation E2 of the first protective layer300 ranges from about 0.02 μm to about 5 μm, or from about 0.2 μm toabout 2 μm.

Next, FIG. 2B illustrates a cross-sectional view of the display device20 in accordance with other embodiments of the present disclosure. Thedifference between the embodiments shown in FIG. 2B and FIG. 2A is thatthe top surface 300 a of the first protective layer 300 in theembodiment shown in FIG. 2B has a concave shape while the top surface300 a of the first protective layer 300 in the embodiment shown in FIG.2A is substantially planar. Moreover, the top surface 212 a of thecontact layer 212 may also has a concave shape.

As shown in FIG. 2B, the wavelength conversion layer 304 located abovethe light-emitting unit 200′ has a seventh thickness T7, and thewavelength conversion layer 304 including the additional portions 304′located above the protective layer 300 has an eighth thickness T8. Insome embodiments of the present disclosure, the seventh thickness T7 maybe defined as the maximum thickness of the wavelength conversion layer304 that is located above both the light-emitting unit 200′ and thecontact layer 212. In some embodiments of the present disclosure, theeighth thickness T8 may be defined as the maximum thickness of thewavelength conversion layer 304 that is located both above theprotective layer 300 and the contact layer 212. In this embodiment, thedifference between the seventh thickness T7 and the eighth thickness T8in one subpixel may be smaller due to the concave shape of the topsurface 300 a and the top surface 212 a, as compared with that of thesubstantially planar top surface 300 a and the top surface 212 a (asshown in FIG. 2A). In addition, in some embodiments of the presentdisclosure, the ninth thickness T9 of the additional portions 304′ thatis closer to the light-emitting unit 200′ may be smaller than the tenththickness T10 of the additional portions 304′ that is farther from thelight-emitting unit 200′ due to the concave shape of the top surface 300a and the top surface 212 a.

Next, FIG. 2C illustrates a cross-sectional view of the display device20 in accordance with other embodiments of the present disclosure. Thedifference between the embodiments shown in FIG. 2C and FIG. 2A is thatthe top surface 300 a of the first protective layer 300 in theembodiment shown in FIG. 2C has a convex shape while the top surface 300a of the first protective layer 300 in the embodiment shown in FIG. 2Ais substantially planar. Moreover, the top surface 212 a of the contactlayer 212 may also has a convex shape.

As shown in FIG. 2C, in this embodiment, the eleventh thickness T11 ofthe additional portions 304′ that is closer to the light-emitting unit200′ may be greater than the twelfth thickness T12 of the additionalportions 304′ that is farther from the light-emitting unit 200′ due tothe convex shape of the top surface 300 a and the top surface 212 a. Inaddition, the reflected light L may be concentrated to increase theillumination efficiency due to the convex surface of the top surface 300a and the top surface 212 a.

Next, FIG. 3A illustrates a cross-sectional view of the display device30 in accordance with some embodiments of the present disclosure. Thedifference between the embodiments shown in FIG. 3A and FIG. 1A is thatthe second insulating layer 110′ in the embodiment shown in FIG. 3Afurther includes a bank portion 110 b.

As shown in FIG. 3A, the bank portion 110 b of the second insulatinglayer 110′ protrudes toward the light shielding layer 306. The bankportion 110 b of the second insulating layer 110′ includes a top surface110 ba. In some embodiments of the present disclosure, the elevation E5of the top surface 110 ba of the second insulating layer 110′ is lowerthan the elevation E2 of the top surface 300 a of the first protectivelayer 300. In such a configuration, the materials of the firstprotective layer 300 may be conserved since the bank portions 110 b ofthe second insulating layer 110′ occupies some of the spaces that areoriginally to be filled in with the first protective layer 300. On theother hand, the elevation E5 of the top surface 110 ba of the secondinsulating layer 110′ may be lower or higher than the elevation E3 ofthe top surface 204 a of the quantum well layer 204.

In some embodiments of the present disclosure, since the secondinsulating layer 110′ includes the bank portions 110 b, thelight-emitting units 200 may be disposed in the trench or the cavitydefined by the bank portions 110 b. In some embodiments, a plurality oflight-emitting units 200 are disposed in the same trench defined by thebank portions 110 b. In other embodiments, each of the light-emittingunit 200 is disposed in a cavity defined by the bank portions 110 bseparately. In addition, each cavity includes a plurality oflight-emitting units 200 disposed therein in accordance with someembodiments.

In addition, the bank portion 110 b may be formed by performing apatterning process to the second insulating layer 110′. The patterningprocess may include a photolithography process and an etching processsuch as a selective etching process. The photolithography process mayinclude, but is not limited to, photoresist coating (e.g., spin-oncoating), soft baking, hard baking, mask aligning, exposure,post-exposure baking, developing the photoresist, rinsing, drying, andother suitable processes. The etching process may include dry etchingprocess or wet etching process.

In accordance with some embodiments of the present disclosure, theelevation E5 of the top surface 110 ba of the second insulating layer110′ is equal to the elevation E2 of the top surface 300 a of the firstprotective layer 300. In accordance with other embodiments of thepresent disclosure, the elevation E5 of the top surface 110 ba of thesecond insulating layer 110′ is higher than the elevation E2 of the topsurface 300 a of the first protective layer 300 (as shown in FIG. 3B).In addition, the second insulating layer 110′ may be a two-layeredstructure or multi-layers stack structure in accordance with someembodiments.

Next, FIG. 4 illustrates a cross-sectional view of the display device 40in accordance with some embodiments of the present disclosure. Thedifference between the embodiments shown in FIG. 4 and FIG. 1A is thatthe top surface 300 a of the first protective layer 300 in theembodiment shown in FIG. 4 includes a plurality of recesses 314. Inother words, the top surface 300 a of the first protective layer 300 hasa pothole structure.

In some embodiments of the present disclosure, the recesses 314 of thetop surface 300 a of the first protective layer 300 may be randomlydistributed. In some embodiments of the present disclosure, the size ofthe recess 314 may range from about 1 nm to about 10 um or from about100 nm to about 2 um. In addition, in such a configuration, the recesses314 of the top surface 300 a of the first protective layer 300 mayprevent the reflected light from being trapped in the first protectivelayer 300 due to the total reflection. Accordingly, the recesses 314 ofthe top surface 300 a may increase or improve the illuminationefficiency of the display device.

In some embodiments of the present disclosure, the recesses 314 of thetop surface 300 a may be formed by a patterning process. The patterningprocess may include a photolithography process and an etching processsuch as a selective etching process. The photolithography process mayinclude, but is not limited to, photoresist coating (e.g., spin-oncoating), soft baking, hard baking, mask aligning, exposure,post-exposure baking, developing the photoresist, rinsing, drying, andother suitable processes. The etching process may include dry etchingprocess or wet etching process.

Next, FIG. 5A illustrates a cross-sectional view of the display device50 in accordance with some embodiments of the present disclosure. Thedifference between the embodiments shown in FIG. 5A and FIG. 1A is thatthe display device 50 further includes a buffer layer 316 disposed onthe light-emitting unit 200.

As shown in FIG. 5A, the buffer layer 316 may be disposed on thelight-emitting unit 200 and the first protective layer 300. The bufferlayer 316 may be disposed between the light-emitting unit 200 and thewavelength conversion layer 304. In some embodiments of the presentdisclosure, the buffer layer 316 may be conformally formed over thelight-emitting unit 200 and the first protective layer 300. In addition,the buffer layer 316 may cover the sidewall 206 s of the secondsemiconductor layer 206. As described above, the buffer layer 316 may bedisposed between the light-emitting unit 200 and the wavelengthconversion layer 304 so that the direct contact between thelight-emitting unit 200 and the wavelength conversion layer 304 may beavoided. Thus, the wavelength conversion layer 304 may be unaffected bythe current or heat produced by the light-emitting unit 200. Asdescribed above, although the display device 50 include the wavelengthconversion layer 304 disposed on the light-emitting unit 200 in theembodiments illustrated in FIG. 5A, the wavelength conversion layer 304may be simply replaced with a transparent material without the functionof wavelength conversion (e.g., without phosphor particles or quantumdot materials). For example, the transparent material may include, butis not limited to, a polymer or glass matrix.

In some embodiments of the present disclosure, the buffer layer 316 maybe an insulator. In some embodiments of the present disclosure, thebuffer layer 316 may include organic materials and/or inorganicmaterials. The buffer layer 316 may be formed of organic insulatingmaterials. The organic insulating material may include, but is notlimited to, polyamide, polyethylene, polystyrene, polypropylene,polyester, polyimide, polyurethane, silicones, polyacrylate,benzo-cyclo-butene (BCB), polyvinylpyrrolidone (PVP), polyvinylfluoride(PVF), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE),polymethylmetacrylate (PMMA), polydimethylsiloxane (PDMS), any othersuitable organic insulating materials, or a combination thereof. Theinorganic insulating material may include, but is not limited to,SiO_(x), SiN_(x), AlO_(x), any other suitable inorganic insulatingmaterials, or a combination thereof.

In addition, the buffer layer 316 may be formed by using chemical vapordeposition (CVD) or spin-on coating. The chemical vapor deposition mayinclude, but is not limited to, low-pressure chemical vapor deposition(LPCVD), low-temperature chemical vapor deposition (LTCVD), rapidthermal chemical vapor deposition (RTCVD), plasma enhanced chemicalvapor deposition (PECVD), atomic layer deposition (ALD), or any othersuitable method.

In some embodiments of the present disclosure, the thickness of thebuffer layer 316 may not be uniform. As shown in FIG. 5A, the bufferlayer 316 located above the first protective layer 300 may have athirteenth thickness T13, and the buffer layer 316 located above thelight-emitting unit 200 has a fourteenth thickness T14. In someembodiments of the present disclosure, the thirteenth thickness T13 ofthe buffer layer 316 is greater than the fourteenth thickness T14 of thebuffer layer 316. That is, the buffer layer 316 disposed directly on thelight-emitting unit 200 may be thinner than the buffer layer 316directly disposed on the first protective layer 300. In such aconfiguration, the intensity of the light emitted from thelight-emitting unit 200 will not be greatly decreased since the bufferlayer 316 disposed on the light-emitting unit 200 is thinner. In someembodiments of the present disclosure, the difference between thethirteenth thickness T13 and the fourteenth thickness T14 may range fromabout 0.001 um to about 5 um or from about 0.05 um to about 2 um. Insome embodiments of the present disclosure, the thirteenth thickness T13of the buffer layer 316 may range from about 0.02 μm to about 5 μm orfrom about 0.1 um to about 2 um. In some embodiments of the presentdisclosure, the fourteenth thickness T14 of the buffer layer 316 mayrange from about 0.02 μm to about 5 μm or from about 0.1 um to about 2um.

Next, FIG. 5B illustrates a cross-sectional view of the display device50 in accordance with other embodiments of the present disclosure. Thedifference between the embodiments shown in FIG. 5B and FIG. 5A is thatthe top surface 316 a of the buffer layer 316 on the first protectivelayer 300 in the embodiment shown in FIG. 5B has a concave shape whilethe top surface 316 a of the buffer layer 316 on the first protectivelayer 300 in the embodiment shown in FIG. 5A is substantially planar.

In addition, as shown in FIG. 5C, the top surface 316 a of the bufferlayer 316 on the first protective layer 300 may have a convex shape inaccordance with other embodiments of the present disclosure.

Next, FIG. 6A illustrates a cross-sectional view of the display device60 in accordance with other embodiments of the present disclosure. Thedifference between the embodiments shown in FIG. 6A and FIG. 5A is thatthe buffer layer 316′ in the embodiment shown in FIG. 6A is adiscontinuous structure while the buffer layer 316 in the embodimentshown in FIG. 5A is a continuous structure.

As shown in FIG. 6A, the buffer layers 316′ within different subpixelsmay be discontinuous. In other words, the buffer layers 316′ fromdifferent subpixels may be separated. In this embodiment, a portion ofthe buffer layers 316′ may be disposed over the light-emitting unit 200while another portion of the buffer layers 316′ may be disposed over thefirst protective layer 300. In particular, the buffer layers 316′ mayentirely cover the top surface 206 a of the second semiconductor layer206, and partially cover the top surface 300 a of the first protectivelayer 300. In some embodiments of the present disclosure, the bufferlayer 316′ extends from the light-emitting unit 200 through thewavelength conversion layer 304 and to the light shielding layer 306.

In some embodiments of the present disclosure, the buffer layers 316′may be formed by a patterning process. The patterning process mayinclude a photolithography process and an etching process such as aselective etching process. The photolithography process may include, butis not limited to, photoresist coating (e.g., spin-on coating), softbaking, hard baking, mask aligning, exposure, post-exposure baking,developing the photoresist, rinsing, drying, and other suitableprocesses. The etching process may include dry etching process or wetetching process.

Next, FIG. 6B illustrates a cross-sectional view of the display device60 in accordance with other embodiments of the present disclosure. Thedifference between the embodiments shown in FIG. 6B and FIG. 6A is thatthe buffer layer 316″ in the embodiment shown in FIG. 6B does not extendto the light shielding layer 306.

As shown in FIG. 6B, the buffer layer 316″ may entirely cover the topsurface 206 a of the second semiconductor layer 206, and partially coverthe sidewall 206 s of the second semiconductor layer 206. The bufferlayer 316″ does not extend along the top surface 300 a of the protectivelayer 300. Similarly, the buffer layers 316″ may be formed by thepatterning process as described above.

Next, FIG. 7A illustrates a cross-sectional view of the display device70 in accordance with some embodiments of the present disclosure. Thedifference between the embodiments shown in FIG. 7A and FIG. 2A is thatthe display device 70 further includes a buffer layer 316 disposed onthe contact layer 212.

As shown in FIG. 7 , the buffer layer 316 may be disposed between thecontact layer 212 and the wavelength conversion layer 310. In someembodiments of the present disclosure, the buffer layer 316 may beconformally formed over the contact layer 212. As described above, thebuffer layer 316 may be disposed between the contact layer 212 and thewavelength conversion layer 310 so that the direct contact between thecontact layer 212 and the wavelength conversion layer 310 may beavoided. Thus, the wavelength conversion layer 310 may be unaffected bythe current or heat produced by the light-emitting unit 200 includingthe contact layer 212.

In some embodiments of the present disclosure, the thickness of thebuffer layer 316 may not be uniform. As shown in FIG. 7 , the bufferlayer 316 disposed directly above the light-emitting unit 200 may bethinner than the buffer layer 316 directly disposed above the firstprotective layer 300 in accordance with some embodiments of the presentdisclosure. In such a configuration, the intensity of the light emittedfrom the light-emitting unit 200 will not be greatly decreased since thebuffer layer 316 disposed on the light-emitting unit 200 is thinner.

Next, FIG. 8 illustrates a cross-sectional view of the display device 80in accordance with some embodiments of the present disclosure. Thedifference between the embodiments shown in FIG. 8 and FIG. 5A is thatthe top surface 316 a″ of the buffer layer 316 on the light-emittingunit 200 in the embodiment shown in FIG. 8 is rougher than the topsurface 316 a′ of the buffer layer 316 on the first protective layer300.

As shown in FIG. 8 , in this embodiment, the top surface 316 a of thebuffer layer 316 may further include the top surface 316 a″ that isdisposed above the light-emitting unit 200 and the top surface 316 a′that is disposed above the first protective layer 300 and out of thelight-emitting unit 200. As describe above, the top surface 316 a″ maybe rougher than the top surface 316 a′. In some embodiments, the surfaceroughness of the top surface 316 a′ may range from about 2 nm to about30 nm. In some embodiments, the surface roughness of the top surface 316a″ may range from about 5 nm to about 100 nm. In some embodiments, thedifference of the surface roughness between the top surface 316 a″ andthe top surface 316 a′ may range from about 3 nm to about 100 nm. Insuch a configuration, the light from the light-emitting unit 200 may beemitted more uniformly so that the conversion efficiency of thewavelength conversion layer 304 may be increased.

In some embodiments of the present disclosure, the rough top surface 316a″ may be formed by an etching process. The etching process may includedry etching process or wet etching process.

Next, FIG. 9A illustrates a partially enlarged portion of the displaydevice 50 in FIG. 5A. As shown in FIG. 9A, the conductive elements 302may include the first conductive elements 302 a and the secondconductive elements 302 b. The first conductive elements 302 a may bedisposed underneath the first terminal S1 of the light-emitting unit200. The first conductive elements 302 a may be disposed between thelight-emitting unit 200 and the second insulating layer 110. Inparticular, some of the first conductive elements 302 a may be disposedbetween the first electrode 208 and the contact structures (e.g., theconductive pads) on the second insulating layer 110; and some of thefirst conductive elements 302 a may be disposed between the secondelectrode 210 and the contact structures (e.g., the conductive pads) onthe second insulating layer 110. On the other hand, the secondconductive elements 302 b may be disposed in the region out of thelight-emitting unit 200. The second conductive elements 302 b may bedispersed in the first protective layer 300 or disposed at the topsurface 110 a of the second insulating layer 110.

In accordance with some embodiments of the present disclosure, aheight-to-width ratio of the first conductive element 302 a ranges fromabout 0.25 to about 0.75 or from about 0.4 to about 0.6. However, itshould be noted that the height-to-width ratio of the first conductiveelement 302 a should not be too small, or the contact yield willdramatically decrease; and the height-to-width ratio of the firstconductive element 302 a should not be too great, or the contactresistance will be too high due to the contact area of a singleconductive element 302 a is too low.

In accordance with some embodiments of the present disclosure, aheight-to-width ratio of the second conductive element 302 b ranges fromabout 0.7 to about 1.3 or from about 0.8 to about 1.2. However, itshould be noted that the height-to-width ratio of the second conductiveelement 302 b should not be too small, or the light being reflected bythe second conductive element 302 b will be nonuniform; and theheight-to-width ratio of the first conductive element 302 a should notbe too great, or the light being reflected by the second conductiveelement 302 b will dramatically decrease.

It should be noted that the height-to-width ratio used herein ismeasured from the cross-sectional structure obtained from the conductiveelement 302. In particular, the variation of height-to-width ratio maybe from about 0% to about 5% due to the process for obtaining thecross-sectional structure. In addition, the “height” of theheight-to-width ratio is defined as the maximum height along a firstdirection of a cross-sectional structure obtained from the conductiveelement 302. The “width” of the height-to-width ratio is defined as themaximum width along a second direction of a cross-sectional structureobtained from the conductive element 302. The above first direction andthe second direction are orthogonal to each other.

For example, FIG. 9B and FIG. 9C illustrate the cross-sectional views ofthe first conductive elements 302 a in accordance with some embodimentsof the present disclosure. Referring to FIG. 9B and FIG. 9C, thecross-sectional structure of the exemplary first conductive element 302a has a maximum height H1 along a first direction A and a maximum widthW1 along a second direction B. The first direction A is orthogonal tothe second direction B. In these examples, the height-to-width ratio ofthe first conductive element 302 a is H1/W1. Moreover, as shown in FIG.9B and FIG. 9C, the cross-sectional structure of the first conductiveelement 302 a may have, but is not limited to, an ellipse shape or anellipse-like shape.

Next, FIG. 9D and FIG. 9E illustrate the cross-sectional views of thesecond conductive elements 302 b in accordance with some embodiments ofthe present disclosure. As shown in FIG. 9D and FIG. 9E, thecross-sectional structure of the exemplary second conductive element 302b has a maximum height H2 along a first direction A and a maximum widthW2 along a second direction B. The first direction A is orthogonal tothe second direction B. In these examples, the height-to-width ratio ofthe second conductive element 302 b is H2/W2. Moreover, thecross-sectional structure of the second conductive element 302 b mayhave, but is not limited to, a circular shape or a circular-like shape.

To summarize the above, the display device provided in the presentdisclosure includes a protective layer having the elevation that islower than the elevation of the upper semiconductor layer of thelight-emitting unit. In such a configuration, less material is requiredfor the protective layer compared to general display devices where theelevation of the protective layer is level with that of the uppersemiconductor layer. In addition, there will be more space for thewavelength conversion layer, which is disposed over the protectivelayer, to fill in. In accordance with some embodiments of the presentdisclosure, the display device includes the protective layer having theelevation that is higher than the elevation of the quantum well of thelight-emitting unit so as to prevent moisture and oxygen from damagingthe quantum well. Furthermore, the protective layer of such a design mayalso prevent shorts or increase the reflectivity.

In addition, in accordance with some embodiments of the presentdisclosure, the display device includes a buffer layer disposed betweenthe light emitting unit and the wavelength conversion layer so that thewavelength conversion layer may be unaffected by the current or heatproduced by the light emitting-unit.

Although some embodiments of the present disclosure and their advantageshave been described in detail, it should be understood that variouschanges, substitutions and alterations can be made herein withoutdeparting from the spirit and scope of the disclosure as defined by theappended claims. For example, it will be readily understood by one ofordinary skill in the art that many of the features, functions,processes, and materials described herein may be varied while remainingwithin the scope of the present disclosure. Moreover, the scope of thepresent application is not intended to be limited to the particularembodiments of the process, machine, manufacture, composition of matter,means, methods and steps described in the specification. As one ofordinary skill in the art will readily appreciate from the presentdisclosure, processes, machines, manufacture, compositions of matter,means, methods, or steps, presently existing or later to be developed,that perform substantially the same function or achieve substantiallythe same result as the corresponding embodiments described herein may beutilized according to the present disclosure. Accordingly, the appendedclaims are intended to include within their scope such processes,machines, manufacture, compositions of matter, means, methods, or steps.

What is claimed is:
 1. An electronic device, comprising: a substrate; adriving circuit disposed on the substrate; a diode electricallyconnected to the driving circuit; and a light shielding elementoverlapping the substrate, wherein a surface of the light shieldingelement has a first width, a cross-sectional-surface of a portion of thelight shielding element has a second width, the second width is greaterthan the first width in a cross-sectional view, and the surface iscloser to the substrate than the cross-sectional surface of the portion.2. The electronic device as claimed in claim 1, wherein the drivingcircuit comprises a first thin-film transistor and a second thin-filmtransistor.
 3. The electronic device as claimed in claim 2, wherein thediode overlaps a channel region of the first thin-film transistor. 4.The electronic device as claimed in claim 1, further comprising awavelength conversion layer overlapping the diode.
 5. The electronicdevice as claimed in claim 4, wherein the wavelength conversion layerhas a curved surface in the cross-sectional view.
 6. The electronicdevice as claimed in claim 1, further comprising an organic layerdisposed between the driving circuit and the diode.
 7. The electronicdevice as claimed in claim 1, wherein the light shielding elementcomprises a black matrix material.